Marques, who held an address on Mountjoy Square in Dublin, is wanted in the US on four charges linked to a website which carried violent, graphic porn depicting the rape and torture of prepubescent children.

He is being held in Dublin on four counts - the advertising of child pornography, distribution of child pornography, conspiracy to advertise child pornography, and conspiracy to distribute child pornography.

On Friday, Justice John Edwards, sitting at the High Court, in Dublin, will rule if Marques (28) will be granted bail.

Speaking under questioning by Attorney General of Ireland, Patrick McGrath, FBI special agent Brooke Donahue said the Bureau still believes Marques is the largest facilitator of porn in the world.

It is alleged that Marques was the sole administrator of an anonymous hosting server called Freedom Hosting. This server held multiple websites where pornographic images were shared.

Donahue told the court that upon inspecting the RAM from Marques computer they found he had made inquiries about getting a Russian visa, and residency and citizen there. They also found a “high quality” scan of a fake United States passport under the name “Edward Thomas Brown.”

Donahue told the court, “He was looking to engage in financial transactions with another hosting company in Russia.”

"My suspicion is he was trying to look for a place to reside to make it the most difficult to be extradited to the US." He rejected claims Marques had carried out the online searches as he was interested in Edward Snowden staying in Russia, adding that the whistleblower had been looking for asylum.

"We do have charges against him and they will not release him.”

The FBI agent said given the seriousness of the offences Marques would would likely "spend the rest of his life in prison."

If convicted in the US he could be sentenced to 100 years in prison.

The court heard that the FBI and Irish police had discovered that large sums of money had passed through Marques’s account in the past year. These included payments sent to Romania and involved Bank of America and Allied Irish Bank accounts.

Irish Detective Inspector Declan Daly said, "I would object bail because I do not believe he would attend his hearing for his extradition."

Marques’s lawyer Remy Farrell said his client had no previous convictions and is entitled to a presumption of innocence.